Correlation of epidermal growth factor receptor with morphological features of colorectal advanced adenomas: a pilot correlative case series.

INTRODUCTION

The epidermal growth factor receptor (EGFR) pathway is important to colorectal carcinogenesis. Although EGFR is described to be overexpressed in adenomas, to the authors' knowledge, its relationship with advanced features in adenomas and as a marker for adenoma progression has not been studied.

METHODS

Initially, 13 polyps (sizes 3 mm-5.5 cm) from a 63-year-old patient were stained for EGFR. Subsequently, a validation group of 95 adenomas from 16 patients were graded semiquantitatively for EGFR staining. Size and villous features of the adenomas were evaluated by 2 independent pathologists and compared with EGFR expression. To be classified as advanced, adenomas needed to be greater than 1 cm and fulfill 1 of the 2 criteria-villous component >20% to 25% or presence of high-grade dysplasia.

RESULTS

In the index case, the large 5.5 cm tubulovillous adenoma had EGFR positivity in all of its neoplastic cells, whereas another 2 cm tubular adenoma with focal villous features had 30% EGFR positivity. All other polyps and normal colonic mucosa were negative for EGFR. In 95 adenomas from 16 additional patients, there was a significant correlation of EGFR positivity with adenoma size ≥1 cm and villous features (all P < 0.001). The odds of EGFR expression in advanced adenomas were 17.3 times higher than nonadvanced adenomas (P < 0.001).

CONCLUSIONS

These findings suggest that EGFR overexpression is associated with advanced colorectal adenomas. Further larger studies are needed to explore EGFR expression as a biomarker for adenoma progression.